BrainBlog

News about our knowledge of the brain and behavior
from Anthony Risser, Ph.D.

Monday, June 25, 2007

Confronted by Primary Progressive Aphasia

From The New York Times:

LivesDiminishing ReturnsBy KATHERINE NICHOLSPublished: June 24, 2007

During the two years leading up to his diagnosis, my husband, a highly respected physician, struggled to communicate and complete work, left me in doubt about his truthfulness, accumulated debt I was unaware of and wrote a series of notes that I found bizarre and degrading. Yet he often seemed so loving and well. I wondered if the insanity began with me.

Sunday, June 24, 2007

Game Theory

From the Scientific American website:

May 20, 2007 The Traveler's Dilemma

When playing this simple game, people consistently reject the rational choice. In fact, by acting illogically, they end up reaping a larger reward--an outcome that demands a new kind of for­mal reasoning

By Kaushik Basu

Lucy and Pete, returning from a remote Pacific island, find that the airline has damaged the identical antiques that each had purchased. An airline manager says that he is happy to compensate them but is handicapped by being clueless about the value of these strange objects. Simply asking the travelers for the price is hopeless, he figures, for they will inflate it.

Instead he devises a more complicated scheme. He asks each of them to write down the price of the antique as any dollar integer between 2 and 100 without conferring together. If both write the same number, he will take that to be the true price, and he will pay each of them that amount. But if they write different numbers, he will assume that the lower one is the actual price and that the person writing the higher number is cheating. In that case, he will pay both of them the lower number along with a bonus and a penalty--the person who wrote the lower number will get $2 more as a reward for honesty and the one who wrote the higher number will get $2 less as a punishment. For instance, if Lucy writes 46 and Pete writes 100, Lucy will get $48 and Pete will get $44.

The Cost of Neurological Diseases, Disorders, and Injuries

Neurological conditions such as stroke and Alzheimer's disease cost Canada nearly $9 billion a year in direct costs, say neurologists who warn the health-care system may not be able to handle increased costs of an aging population.

Friday's report from the Canadian Institute for Health Information, titled The Burden of Neurological Diseases, Disorders and Injuries in Canada is a consensus report by neurologists who tallied the costs of 11 conditions they treat:

Thursday, June 14, 2007

Autophagy

(PHILADELPHIA) – Many age-related neurological diseases are associated with defective proteins accumulating in nerve cells, suggesting that the cell’s normal disposal mechanisms are not operating correctly. Now, researchers at the University of Pennsylvania School of Medicine have discovered a molecular link between the cell’s two major pathways for breaking down proteins and have succeeded in using this link to rescue neurodegenerative diseases in a simple animal model. The study appears this week in Nature.

The cell has two internal pathways for breaking down proteins. The ubiquitin-proteasome pathway marks unwanted proteins with ubiquitin tags and shuttles them for rapid breakdown to a complicated structure called the proteasome. The second is the autophagy-lysosomal system, a more general process in which proteins are surrounded by membranes inside the cell for bulk digestion.

“The dogma has been that the autophagy-lysosomal and the proteasomal systems are trains that run on different tracks, with similar purposes, but no point of intersection,” explains senior author J. Paul Taylor, MD, PhD, Assistant Professor of Neurology. “The new finding directly challenges this thinking by showing that one system can be induced to compensate for the other. Cells are able to shift proteins between the systems. We think that this molecular link can be used to benefit a wide variety of neurodegenerative diseases because accumulation of toxic proteins is a common underlying feature of age-related neurodegeneration.”

Sunday, June 10, 2007

Upcoming Event: Bilbao, Spain (04-07 July 2007)

From the INS website:

"The 2007 Mid-Year meeting is a collaboration between [the International Neuropsychological Society] INS, the Federation of Spanish Neuropsychological Associations and the Spanish Psychiatry Society. The theme for this meeting is "Advances in Basic and Clinical Neuropsychology". It promises to be a scientifically stimulating meeting, with over 500 abstracts being presented.

The meeting will be held on July 4 -7, 2007 at the Palacio de Congresos y de la Musica Euskalduna."

Additional information, including the program, can be found on the INS website: click here

Neuropsychology Abstract of the Day: Olfaction and Dementia

Division of Neuroscience, The Medical School, University of Birmingham, UK.

Lewy-type pathology is a characteristic of a number of neurodegenerative disorders, including Parkinson's disease and dementia with Lewy bodies. Thus far, the definitive diagnosis of these dementias can only be confirmed at post-mortem. However, it is known that the loss of smell (anosmia) is an early symptom in patients who develop dementia, and the use of the smell test has been proposed as an early diagnostic procedure. The aim of this study was to understand further the extent of Lewy pathology in the olfactory system of patients with neurodegenerative disorders. Post-mortem tissue from 250 subjects was obtained from the OPTIMA brain bank. Five areas of the olfactory pathway were examined by immunolabelling for alpha-synuclein - a major component of Lewy pathology: the olfactory tract/bulb (n = 79), the anterior olfactory nucleus in the lateral olfactory gyrus (n = 193), the region of olfactory projection to the orbito-frontal cortex (n = 225), the hippocampus (n = 236) and the amygdala (n = 201). Results show that Lewy pathology affects different parts of the olfactory pathways differentially, suggesting a specific pattern of development of pathology. Clinical Parkinson's disease is most likely to be identified if the orbito-frontal cortex is affected, while the diagnosis is less likely if the pathology is restricted to the olfactory bulb or tract. These results suggest that pathology in the olfactory bulb and tract occurs prior to clinical signs of Parkinson's disease. Furthermore, the results presented here provide further evidence supporting the possible value of a smell test to aid the clinical diagnosis of neurodegenerative diseases.

Thursday, June 07, 2007

Upcoming Event: Twin Cities, 08 June 2007

Presented by:Leigh Turner, PhDAssociate Professor and William Dawson Scholar in the Biomedical Ethics Unit and Department of Social Studies of Medicine, McGill University

Orthopaedic surgery, cardiac care, dental surgery, and other procedures are all available for purchase in the global health services marketplace. Americans unable to afford health care in the United States are arranging treatment in India, Singapore, Thailand, and other countries. Proponents of "medical tourism" argue that a global market in health services will promote consumer choice, foster competition among hospitals, and reduce the cost of health care in the United States. Sceptics raise concerns about patient safety, information disclosure to patients, quality of care, and liability issues. A global market in health services will have profound consequences for health insurance, delivery of health services, public health, patient-physician relationships, and how we understand the relationship between medicine and the marketplace. This presentation examines social and economic dimensions of medical tourism and explores ethical issues raised by the emergence of a global market in health services.

OBJECTIVE: To evaluate the literature discussing the use of modafinil in the treatment of residual symptoms of fatigue in patients with depression. DATA SOURCES: PubMed (1966-March 2007) and International Pharmaceutical Abstracts (1970-March 2007) were searched using the key words modafinil and depression. A manual search of the reference section of the articles retrieved was conducted to identify articles not indexed in either of these sources. STUDY SELECTION AND DATA EXTRACTION: All articles published in English were evaluated. Studies were included if modafinil was used to treat patients with residual fatigue from depression and the effects were measured with validated fatigue subscales. DATA SYNTHESIS: One retrospective study, 5 open-label trials, and 2 randomized controlled clinical trials met the inclusion criteria for assessment of residual symptoms of fatigue as assessed by commonly used fatigue subscales after modafinil administration. Although improvement with fatigue has occurred with modafinil therapy, literature regarding the topic is limited by the lack of well-controlled clinical trials. Modafinil does appear to improve residual fatigue with depression as evidenced by open-label trials; however, the efficacy of this agent has not been duplicated in randomized controlled trials. The open-label trials that have been conducted often had no comparator and a small number of patients. In addition, outcome measures used in the studies were not consistent between trials. Modafinil appears to be well tolerated, with the main adverse effects being headache and nausea. CONCLUSIONS: Open-label trials indicate that modafinil may be effective in ameliorating fatigue associated with depression; however, this effect has not been reproduced in randomized, double-blind, placebo-controlled clinical trials. Therefore, the use of modafinil for the treatment of residual fatigue is not recommended due to the lack of reproducible data of its efficacy. Long-term, adequately powered clinical trials should be conducted to determine its place in therapy.

The Fine Points of Forgetfulness

From today's New York Times:

Forgetting May Be Part of the Process of Remembering By BENEDICT CAREYJune 5, 2007

Whether drawing a mental blank on a new A.T.M. password, a favorite recipe or an old boyfriend, people have ample opportunity every day to curse their own forgetfulness. But forgetting is also a blessing, and researchers reported on Sunday that the ability to block certain memories reduces the demands on the brain when it is trying to recall something important.

The study, appearing in the journal Nature Neuroscience, is the first to record visual images of people’s brains as they suppress distracting memories. The more efficiently that study participants were tuning out irrelevant words during a word-memorization test, the sharper the drop in activity in areas of their brains involved in recollection. Accurate remembering became easier, in terms of the energy required.

Blocking out a distracting memory is something like ignoring an old (and perhaps distracting) acquaintance, experts say: it makes it that much harder to reconnect the next time around. But recent studies suggest that the brain plays favorites with memories in exactly this way, snubbing some to better capture others. A lightning memory, in short, is not so much a matter of capacity as it is of ruthless pruning — and the new study catches the trace of this process at it happens.

OBJECTIVE: The worldwide prevalence estimates of attention deficit hyperactivity disorder (ADHD)/hyperkinetic disorder (HD) are highly heterogeneous. Presently, the reasons for this discrepancy remain poorly understood. The purpose of this study was to determine the possible causes of the varied worldwide estimates of the disorder and to compute its worldwide-pooled prevalence. METHOD: The authors searched MEDLINE and PsycINFO databases from January 1978 to December 2005 and reviewed textbooks and reference lists of the studies selected. Authors of relevant articles from North America, South America, Europe, Africa, Asia, Oceania, and the Middle East and ADHD/HD experts were contacted. Surveys were included if they reported point prevalence of ADHD/HD for subjects 18 years of age or younger from the general population or schools according to DSM or ICD criteria. RESULTS: The literature search generated 9,105 records, and 303 full-text articles were reviewed. One hundred and two studies comprising 171,756 subjects from all world regions were included. The ADHD/HD worldwide-pooled prevalence was 5.29%. This estimate was associated with significant variability. In the multivariate metaregression model, diagnostic criteria, source of information, requirement of impairment for diagnosis, and geographic origin of the studies were significantly associated with ADHD/HD prevalence rates. Geographic location was associated with significant variability only between estimates from North America and both Africa and the Middle East. No significant differences were found between Europe and North America. CONCLUSIONS: Our findings suggest that geographic location plays a limited role in the reasons for the large variability of ADHD/HD prevalence estimates worldwide. Instead, this variability seems to be explained primarily by the methodological characteristics of studies.

Brains, Thumbs, and Great Attentional Abilities

Try reading this article to the end without checking e-mail. Find you can't? Before making assumptions of addictive behaviour, you should know there's a positive side to switching tasks often.

You may actually be training your brain to become faster and stronger.

Studies are beginning to show that cellphone-toting execs and Facebook-friendly teens may be multi-tasking their way into taking on even more, by rewiring their brains to handle it.

The action of using a cellphone or e-mail has an immediate effect on the brain. Answering calls and thumbing texts prepares the human brain to take on such tasks — because its circuitry adapts to the environment it's presented with.

"People will often ask me, 'Are kids today different to kids 20 years ago?' Well, yes, they are. Because the world is different, their brains have wired up in a different way," explains Dr. Martin Westwell, deputy director of Institute for the Future of the Mind at Britain's Oxford University.

For a change, malleable young brains aren't the only ones to benefit. As Westwell points out, "Even during adulthood this happens. The environment in which we find ourselves is really reflected in the way our brain cells rewire."

In fact, Westwell thinks people who grew up with cellphones and instant messaging aren't necessarily better at juggling tasks. Surprisingly, a study he conducted found 35- to 39-year-olds were more able to return to difficult mental tasks after being interrupted by nagging cellphone calls than their 18- to 21-year-old counterparts.

"The older group are just better at switching attention," Westwell says. "What we suspect is, as you get older you have to do more of this multi-tasking."

Sunday, June 03, 2007

New Book: Cerebrum 2007

Picked up a nice-looking new book this afternoon, the first issue of a planned yearly anthology by The Dana Foundation: Cerebrum 2007, with a foreward by Bruce McEwen. The softcover book includes more than a dozen contributions on neuroscience topics ranging from stroke prevention to neuroimaging biomarkers in drug development.

Department of Psychology, University of Alberta, Edmonton, Alberta, Canada.

A well-known challenge for research in the cognitive neuropsychology of aging is to distinguish between the deficits and changes associated with normal aging and those indicative of early cognitive impairment. In a series of 2 studies, the authors explored whether 2 neurocognitive markers, speed (mean level) and inconsistency (intraindividual variability), distinguished between age groups (64-73 and 74-90+ years) and cognitive status groups (nonimpaired, mildly impaired, and moderately impaired). Study 1 (n = 416) showed that both level and inconsistency distinguished between the age and 2 cognitive status (not impaired, mildly impaired) groups, with a modest tendency for inconsistency to predict group membership over and above mean level. Study 2 (n = 304) replicated these results but extended them because of the qualifying effects associated with the unique moderately impaired oldest group. Specifically, not only were the groups more firmly distinguished by both indicators of speed, but evidence for the differential contribution of performance inconsistency was stronger. Neurocognitive markers of speed and inconsistency may be leading indicators of emerging cognitive impairment. (c) 2007 APA, all rights reserved

Friday, June 01, 2007

Wartime Traumatic Brain Injuries (TBIs)

A long road backWith so many service members affected by traumatic brain injuries, neuropsychologists are ramping up diagnosis and treatment

By Christopher MunseyMonitor staffPrint version: page 34

Traumatic brain injury (TBI) has been called the "signature injury" of the Iraq war.

Most commonly, the injuries are caused by improvised explosive devices, or IEDs, the makeshift bombs insurgents frequently use to attack U.S. forces.

Even if soldiers are not directly hit, the shockwaves of these explosions can violently shake their brains or send shrapnel into their helmets. The result is often an injury that's much like a boxer hit with a knock-out punch.

Thanks to excellent medical care and advanced body armor, service members are surviving injuries that would have killed them in previous wars. But with that survival often comes brain damage, a decrease in cognitive abilities and a lessening of emotional self-regulation.

Psychologists, particularly neuropsychologists, are stepping in to assess the damage, help patients learn new strategies to compensate while their brains recover, and raise public awareness of the increasing number of servicemen and women with TBIs. In fact, 1,977 service members were treated for them at Defense and Veterans Brain Injury Center (DVBIC) sites from January 2003 to February 2007.